The present invention relates to a compressed gas filled circuit breaker and, particularly, to a circuit breaker of the so- called electromagnetic repulsion type in which a current due to the discharge of a capacitor flows through a driving coil which exerts an electromagnetic repulsive force on movable contacts to break the circuit.
The conventional circuit breaker of this type employs an insulator construction, and the energy stored in the capacitor for driving the contacts must be supplied through an insulating transformer from the energy source on the ground side of the breaker system. Also the control signal for causing discharge of the capacitor is transmitted by a photoelectric signal from the ground side to the high voltage side.
It is well known that insulating transformers are expensive. This disadvantage as well as the large size thereof becomes more severe when the rated voltage thereof is high because the number of connections is increased correspondingly. Further, the photoelectric system through which the control instruction is transmitted and converted is also expensive.
Recently the use of a circuit breaker employing the so- called tank type structure has been proposed. Such devices have anti-shock properties and durability due to the use of SF.sub.6 gas which exhibits good attributes and causes rapid extinction of the arc.
It has been attempted to incorporate the former system, using an insulating transformer, with the latter tank type gas filled circuit breaker in order to obtain the advantages of the latter. However, the incorporation of an insulating transformer in the tank type gas filled circuit breaker has been difficult. It is very difficult to transmit energy to the high potential side because the size of the insulating transformer is large with respect to the size of the tank. Also since the control portion for controlling the discharge of the capacitor is positioned in the high potential side and hence inside the tank, the maintenance thereof is difficult. On the other hand should the energy be derived from the tank, high voltage bushings are required.